GPS is the abbreviation of a global positioning system developed by the Pentagon. The GPS includes a plurality of GPS satellites and a GPS receiver. The plurality of GPS satellites are arranged by four in each of six circular orbits of an inclination angle of 55°. The plurality of GPS satellites transmits their own position information signals while moving in a cycle of about 12 hours. The GPS receiver receives position information signals from at least four or more GPS satellites among the plurality of GPS satellites, detects its distances from the GPS satellites and position vectors of the GPS satellites, and calculates its own position vector. A navigation system including the GPS receiver maps its own position vector calculated from the GPS receiver on map data, and displays the mapped position vector. The navigation system provides, as a supplementary service, a road guidance service for informing the shortest path from a current position on a map to a user's destination. Therefore, a user can more easily find a way to her own destination by carrying the navigation system.
FIG. 1 illustrates a block diagram of a construction of a portable terminal for recognizing an image using a camera according to the conventional art. As illustrated in FIG. 1, a navigation system is integrated with a camera 104. The navigation system can include a command input part 112, a GPS receiver 100, a map data storage part 108, a sensor 110, an image processor 106, and a controller 102. The command input part 112 receives an input of a user's operation command. The GPS receiver 100 receives a position information signal transmitted by a GPS satellite. The map data storage part 108 stores map data. The sensor 110 detects a direction angle of the camera 104 and an inclination angle through a geomagnetic sensor and an angle meter. The image processor 106 processes an image captured by the camera 104. The controller 102 captures an image photographed by the camera 104 at a predetermined time interval, searches the map data storage part 108 for buildings of position information consistent with respective buildings within the captured image, and matches them with each other.
However, the conventional art has a disadvantage of consuming much time because having to display geographic information on several features. In this case, the portable terminal has to recognize one feature and display geographic information and, after that, again recognize a next feature and display geographic information. In theory, assuming that number of features required to display geographic information is equal to ‘n’ and a time taken to recognize one feature is equal to ‘t’, a time taken to display geographic information on the total features is equal to ‘n*t’. However, because the ‘t’ can be a long time, a user has to spend much time to obtain interested information.